I don't have a sf gas forno, but I'm using LP gas. LPG has a very high energy content. It burns hot and with no soot, so it's a clean way to get a high temperature. It's certainly easier to regulate and keep a consistent temperature.
I wouldn't scoff at it without trying it. You taste the pizza and not the wood smoke. I think some people confuse the smoke residue for dough taste.
Youíre right that, compared to wood, LP and NG both have a lot of energy density (more than 3X as much useable energy per kg). However, the energy density of the fuel is not what bakes a pizza. The rate at which the oven converts fuel to energy, at the very least, is what you need to know. The SF website (http://www.sfallestimenti.it/english/gas_ovens.html
) says the oven has a max heat output of 34Kw (to be correct, it is kW not Kw as shown on the website Ė further, Iím assuming they actually mean kWh not kW as kW is meaningless in this context). 34 kWh = 116,013 Btu. Say you can squeeze about 6,200 Btu/lb out of oak or another similar hardwood, a 34 kWh oven is about the same as burning 19lbs/hr oak in a WFO. I donít need that much wood to keep the oven hot, and my oven doesnít get very saturated only getting used once/week, so it would take more wood for me than for an oven used every day. I donít think it will surprise anyone that SF put a large enough burner in their oven.
Itís one thing to replace a wood fire with a similar energy output gas fire. Thatís very easy. I think the more important questions are around the things that donít necessarily change linearly with the fuel change. A couple things that come to mind:
- There is a big difference in the heat transfer mechanism. Compared to wood, gas will have much more convection and much less radiation. Maybe itís good not to have a strong IR source on one side of the oven? Maybe itís not good to lack the strong IR of the rolling flame across the top of the oven?
- There is going to be a difference in the amount of water produced. I have not run all the numbers, so I donít know which produces less. Compared to a large wood fire, Iíd guess gas produces less. Compared to a large coal bed with only a small log burning, gas may produce more. According to SF, at wide open throttle, the SF is burning 1.2kg propane/hr. That would produce right at 2kg water/hr (4*18/44*1.2). I have no idea if this is good, bad, or indifferent to pizza quality as compared to wood.
- As noted in the original quote, gas is not wood. Perhaps there is a difference in flavor? I've eaten a lot of NP at a lot of different restaurants, and I've never tasted what I would call "wood smoke.Ē Itís hard to imagine a wood fire having much of a direct flavor impact at temperatures that high and bake times that short. Maybe? Iíve eaten a lot of pies baked with gas in my grill Ė some with wood assist and some without. I canít say I noticed a flavor difference either way. Those were baked at a lower temp (750F) and for a longer time (2:15) than a NP WFO, so if there is a difference, I would think it would have been more noticeable.
I'm not sure that bread fermented in a modern environmental-controlled cabinet and baked in a modern oven is worse that bread baked in an old stone oven.
What does this have to do with the topic at hand? I thought this was about Neapolitan pizza?